Environment

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AP Photo/Charlie Riedel
A wing-mounted generator emits particles of silver iodide during a cloud seeding mission.

Seeding the Clouds for Drought Relief

February 22, 2010 01:00 PM
by James Sullivan
Venezuelan President Hugo Chavez seeds the clouds above his country to combat a drought that has brought Venezuela’s reservoirs to their lowest levels in years.

Hold the Rain Dance

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Venezuela is experiencing its worst drought in decades, thanks to the El Niño climate pattern that has conversely brought fertile conditions to farmers in the U.S. The drought has led to a dire political situation in the country, as hydroelectric dams falter, causing blackouts and protests, reports The Guardian.

President Hugo Chávez has enlisted the aid of Cuban pilots to combat the droughts through a program of cloud seeding. Venezuela's cloud seeding ambitions gained attention last November heading into the country's dry season. 

Of his cloud-seeding intentions Chavez said, “Any cloud that comes in my way, I’ll hurl a lightning bolt at it. Tonight I’m going out to bombard.”

In November 2009, The Associated Press reported that seeding equipment was being fitted to C-130 Hercules transport planes by Cuban specialists, and that the first target areas were those which feed the Guri hydroelectric dam.

In an interview with Scientific American, cloud-seeding expert Arlen Huggins expressed doubt about the effectiveness of cloud-seeding for fighting a drought. “If [China is] in a drought, they wouldn’t be able to draw enough from cloud seeding, just for the lack of clouds. You treat the storms you have, so cloud seeding certainly isn’t going to bring you out of a drought. The best time to do cloud seeding is when you have normal levels, or higher-than-normal levels, of precipitation. Then you could save the extra water in a reservoir for when you are in a drought. It certainly won’t bring you out of one.”

The practice of cloud-seeding garnered considerable attention in the run up to the Beijing Olympics, when China guaranteed clear skies for its opening ceremony, and took steps toward fulfilling the promise by launching over 1,000 rain dispersal rockets into the skies above the city.

China is the world’s most active cloud seeder, and employs over 30,000 people across the country to operate its arsenal of weather control guns. In early November overzealous seeding and a sudden drop in temperature led to a blizzard in Beijing, the city’s earliest snowfall in a decade.

Background: Cloud-seeding and its dangers

Cloud seeding is a means of modifying weather patterns by sending chemicals into the atmosphere that induce or suppress precipitation. China has been engaging in the practice for years, shooting shells with silver iodide into the atmosphere to encourage or prevent rainfall for farmers, fight fires and relieve drought.

Cloud seeding is a controversial practice and its benefits are often difficult to track. Scientists cannot definitively say how much rain would have fallen if seeding did not take place, and large storms are often unaffected by seeding attempts.

The United States, which experimented with cloud seeding at various points during the 20th century, has since moved away from the process.

Asia Times Online reported in 2007 that cloud seeding shells and rockets sometimes go astray, “damaging homes and injuring inhabitants.” The publication notes that, in 2006, a pedestrian in Chongqing was killed by part of a rain cannon after it misfired. In addition, some Chinese citizens have expressed concern over the environmental and health ramifications of cloud seeding.

An article on the Dartmouth Toxic Metals Research Program Web site suggests that “Cloud-seeding technology raises some concerns that adding chemicals to clouds would pollute the air, water or earth.” However, organizations that support cloud seeding argue that the quantities of silver iodide used are too small to be toxic.

Related Topic: Cloud-seeding causes man to explode twice

Four years ago a rogue cloud-seeding shell killed a Chinese man, Wang Diange, and then blew up his corpse a few days later. The incident raised concerns about the safety of cloud seeding.
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